1. Field of the Invention
The present invention relates to lubricating oil compositions and watches using the same. More particularly, the invention relates to lubricating oil compositions favorably used as lubricating oils particularly for movable portions including slide and rotation portions of watches, and watches using the lubricating oil compositions.
2. Description of the Prior Art
Watches are broadly divided into mechanical watches and electronic watches. The mechanical watches are those which are operated by the use of a spiral spring as the driving source, while the electronic watches are those which are operated by the use of electric power. In both electronic watches and mechanical watches, tram wheel portions wherein gears to drive the hour hand, the minute hand and the second hand gather and a movable portion such as a lever are combined to display the time.
In the field of watch manufacture, only the mechanical watches were invented but any electronic watch was not invented in the initial stage. In order to make smooth operation of mechanical watches, lubricating oil is poured into the movable portion of the rotary device. In mechanical watches, a force from the spiral spring is always applied to the train wheel portions, so that a precious stone (ruby) is provided as a tenon receiver of the train wheel portions to reduce frictional wear, and the rotary gear is made of a relatively highly wear-resistant stable metal such as iron.
After that, with the spread of batteries, electronic watches have been put on the market, and recently, the present applicant has proposed watches which are operated for a certain period of time by the use of primary battery and watches which are continuously operated by the use of a combination of a light power-generation element or a thermal power-generation element and a rechargeable battery even if the battery is not changed. Further, uses of watches have been widened, and watches for sky diving or scuba diving have become commercially available. In the sales of the watches, not only finished articles of watches but also modules thereof have been made available for purchase.
Thus, because of the extension of uses or sales manner and transfiguration of modes of watches, watch modules are desired to have moisture resistance, heat resistance, low-temperature resistance, thermal impact resistance and long life. As materials to manufacture watches, brass has excellent processability and then plastic members have been used, so that corrosiveness of lubricating oils to metals or plastics needs to be reduced.
The present applicant has used, as a lubricating oil for watch, for example, Synt-Lube available from MOEBIUS Co. This lubricating oil is a mixture of synthetic hydrocarbons with ether and alcohol groups. The base oil of the lubricating oil is a mixture of alkyl-aryloxydibutylene glycols, and to the base oil, 1.6% of an alkylphenoxy acid, less than 1% of 2,6-di-tert-butyl-4-methylphenol, C3-C14 Zn-dialkyl dithiophosphate, etc. are added as additives (Synt-Lube MSDS available from MOEBIUS Co., transcribed from catalogue).
In the use of this currently used lubricating oil (Synt-Lube available from MOEBIUS Co.), operational failure of watch such as stoppage occasionally takes place. The present applicant owns service stations to collect and repair watches and has investigated the operational failure of these watches. As a result, more than 10 years ago, the present applicant found problems such as the lubricating oil changing into a gel and corrosion of the plastic members or metals.
The above-mentioned lubricating oil is a medium-viscosity lubricating oil having a kinematic viscosity (JIS K2283-1979) of 27 cSt at 50° C. and 2600 cSt at −20° C., and there is a problem that if the lubricating oil is used for all the train wheel portions, a phenomenon of spreading-out of the lubricating oil occurs by viscosity decrease at a high temperature of 80° C.
To solve the above problem, the present applicant uses a lubricating oil of high viscosity (kinematic viscosity (JIS K2283-1979): 45 cSt at 50° C., 13500 cSt at −20° C.) for only the place of high driving power and avoids use of the lubricating oil of high viscosity for the place of low driving power because the whole viscosity is increased to raise power consumption.
On this account, there is brought about a problem that spreading out of the lubricating oil takes place at a high temperature of 80° C. depending upon the gears of the train wheel portions. In the case of a low temperature of −10° C., there is another problem in that driving becomes infeasible because of viscosity increase of the lubricating oil.
Therefore, the present applicant uses a lubricating oil of low viscosity (kinematic viscosity (JIS K2283-1979): 16 cSt at 50° C., 840 cSt at −20° C.) for only the place of low driving power (rotor section) to avoid the problem given at the low Temperature of −10° C. In this case, however, the viscosity is strikingly lowered at a high temperature of 80° C., resulting in a problem of spreading-out of the lubricating oil. In addition, the watches have a problem at low temperatures, that is, operation failure takes place when the temperature becomes lower than −10° C.
Further, there are many kinds of lubricating oils, namely, three kinds of medium-viscosity, high-viscosity and low-viscosity lubricating oils, and they must be used properly in the manufacture or repair of the watches. As a result, there is a possibility of wrong use of the lubricating oils.
In the use of the currently used lubricating oils, as described above, there are various problems such as a problem of spreading-out of the lubricating oil at high temperatures, a problem of feeding oil to the place of low driving power at low temperatures, a problem of gelation, a problem of change of properties such as corrosion of plastic members or metals and a problem of too many kinds of lubricating oils used.
The present invention has been made to solve such problems associated with the prior art as described above, and it is an object of the invention to provide a lubricating oil composition which enables a watch to operate in the temperature range of −30 to 80° C. with one kind of a lubricating oil, is free from change of properties over a long period of time, enables a life of watch battery to last long and is favorable as a watch lubricating oil, and to provide a watch using the composition.
It is another object of the invention to provide a lubricating oil composition which is free from change of properties over a long period of time, enables a life of watch battery to last long and is favorable as a watch lubricating oil, and to provide a watch using the composition.